1. Field of the Invention
The invention relates generally to the field of epilepsy treatment, and more particularly to antiepileptic pharmaceutical compositions for oral administration.
2. Background of the Art
Phenytoin sodium is a known antiepileptic compound. Phenytoin, phenytoin sodium, and procedures for their manufacture are well known, see for example Kao et al U.S. Pat. No. 4,696,814 issued Sep. 29, 1987; Fawzi et al U.S. Pat. No. 4,642,316 issued Feb. 10, 1987; and Henze U.S. Pat. No. 2,409,754, issued Oct. 22, 1946, all of which are incorporated herein by reference.
Phenytoin sodium is commercially available as an oral extended release pharmaceutical composition. Drug release problems associated with these pharmaceutical compositions have resulted in numerous recalls for failure to meet dissolution requirements.
Consequently, there is a need and a desire for reliable extended release phenytoin sodium pharmaceuticals.
The extended release pharmaceutical composition of the present invention comprises an admixture of phenytoin sodium and an erodible matrix, wherein the matrix comprises a pharmaceutically acceptable binder(s), diluent(s), or combination thereof. The matrix releases the drug from the pharmaceutical composition both initially and after storage for 12 months at 25 degrees centigrade/60% relative humidity over about a two hour period when pharmaceutical compositions made from 100-300 mg phenytoin sodium, preferably 200 to 300 mg, are measured in-vitro by dissolution testing in 900 ml of water using a basket rotating at 100 rpm. The use of an erodible matrix imparts reliability to the in-vitro dissolution profile of the pharmaceutical composition of the present invention.